• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.135-142
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• 2016

Objective: The purpose of this study was to investigate the acute effect of walking on high heels on the behavior of fascicle length and activation of the lower limb muscles. Methods: Twelve healthy inexperienced high heel wearers (age: $23.1{\pm}2.0yr$, height: $162.4{\pm}4.9cm$, weight: $54.4{\pm}8.5kg$) participated in this study. They walked in high heels (7 cm) and barefoot on a treadmill at their preferred speed. During the gait analysis, the lower limb joint kinematics were obtained using a motion analysis system. In addition, the changes in fascicle length and the level of activation of the medial gastrocnemius (MG) were simultaneously monitored using a real-time ultrasound imaging technique and surface electromyography, respectively. Results: The results of this study show that the MG fascicle operates at a significantly shorter length in high heel walking ($37.64{\pm}8.59mm$ to $43.99{\pm}8.66mm$) in comparison with barefoot walking ($48.26{\pm}9.02mm$ to $53.99{\pm}8.54mm$) (p < .05). In addition, the MG fascicle underwent lengthening during high heel walking with relatively low muscle activation while it remained isometric during barefoot walking with relatively high muscle activation. Conclusion: Wearing high heels alters the operating range of the MG fascicle length and the pattern of muscle activation, suggesting that prolonged wearing of high heels might induce structural alterations of the MG that, in turn, hinder normal functioning of the MG muscle during walking.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.274-277
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• 2003

The purpose of this study was to determine the range of resistive index(RI) of the cranial pancreaticoduodenal artery(cPDA) in the normal dog's and to assess the possibility of clinical application of RI for diagnosing a pancreatitis. Five patients with acute pancreatitis and 17 healthy adult beagle dogs were used. Duplex color Doppler ultrasonographic examination was performed by using a real-time scanner with 11-MHz linear-array transducer. The dogs were restrained in dorsal recumbency without the use of chemical agent. The mean RI of the normal pancreas(0.63$\pm$0.04) was significantly(t = 5.79, p = 0.001) different from acute pancreatitis dog(0.75$\pm$0.04). Duplex color Doppler ultrasonography was an useful technique for detecting and measuring RI of the cPDA. The evaluation of RI of the cPDA may be a valuable supportive diagnostic procedure for evaluating the pancreatitis or suspected in dogs.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.435-440
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• 2020

Single-beam acoustic tweezers that are capable of manipulating micron-size particles in a non-contact manner have been used in many biological and biomedical applications. Current single-beam acoustic tweezer systems developed for in vitro experiments consist of a function generator and a power amplifier, thus the system is bulky and expensive. This configuration would not be suitable for in vivo and clinical applications. Thus, in this paper, we present a portable single-beam acoustic tweezer system and its performances of trapping and manipulating micron-size objects. The developed system consists of an Field Programmable Gate Array (FPGA) chip and two pulsers, and parameters such as center frequency and pulse duration were controlled by a Personal Computer (PC) via a USB (Universal Serial Bus) interface in real-time. It was shown that the system was capable of generating the transmitting pulse up to 20 MHz, and producing sufficient intensity to trap microparticles and cells. The performance of the system was evaluated by trapping and manipulating 40 ㎛ and 90 ㎛ in diameter polystyrene particles.

• Clinical and Experimental Reproductive Medicine
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• v.13 no.1
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• pp.67-75
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• 1986

Follicle monitoring in the normal and clomiphene·stimulated cycles were analyzed in the Seoul IVF and ET (In vitro fertilization and embryo transfer) program. Ovarian follicular diameters were measured by the real·time sector scanner and plasma estradiol levels were assayed by radioimmunoassay methods during periovulatory period. The maximum follicular sizes of the clomiphene-stimulated and normal cycles were 21.1+-3.4mm and 19.2+-0.8mm, respectively. The peak levels of plasma estradiol in the clomiphene-stimulated and normal cycles were 10538+-553.6ng/ml and 298.3+-39.6pg/ml, respectively. Daily growth rate of the follicular diameters of the clomiphene-stimulated and normal cycles were 2.1mm and 1.9mm, respectively. Mean follicular number of the clomiphene-simulated and normal cycles were 2.28+-1.12 and 1.12+-0.21, respectively. There was a good statistical correlation between the mean follicular diameters and the plasma estradiol levels in the normal ovulatory and c1omiphene-stimulated ovulatory menstrual cycles (p<0.05). Our data revealad that the mean follicular diameter and the plasma estradiol level prior to HCG administration in IVF and program should reach at the level of 17.8+-3.0mm and 949.4+-487.1 pg/ml, respectively.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.61-68
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• 2007

When an active muscle is stretched, its steady-state isometric force following stretch is greater than that of a purely isometric contraction as the corresponding muscle length, referred to as force enhancement (FE). The purpose of this study was to investigate possible effects of muscle architecture on the FE. While subject performed maximal isometric dorsiflexion (REF) and isometric-stretch-isometric dorsiflexion (ECC) contractions, ankle joint angle and dorsiflexion torque using a dynamometer and electromyography of the tibialis anterior and the medical gastrocnemius muscles were measure. Simultaneously, real-time ultrasound images of the tibialis anterior were acquired. Regardless of the speed of stretch of the ECC contractions. the torques produced during the isometric phase following stretch ($37.3{\pm}1.5\;Nm$ ($10{\pm}3%$ FE) and $38.3{\pm}1.5$ ($12{\pm}3%$ FE) for the ECC contractions with $15^{\circ}$/s and $45^{\circ}$/s stretch speeds, respectively) were greater than those of the REF contractions ($34.5{\pm}2.5\;Nm$). Moreover, the amount of FE was found to be stretch speed dependent. Angles of pennation ($\alpha$) during the isometric phase following stretch were the same for the REF ($15{\pm}1^{\circ}$) and the ECC ($14{\pm}1^{\circ}$(LS), $15{\pm}1^{\circ}$(LF)). During the same phase, muscle thicknesses were the same ($14.9{\pm}0.6$, and $14.9{\pm}0.5\;mm$ for the REF and the ECC contractions, respectively). For a large limb muscle, the tibialis anterior muscle, a similar amount of force enhancement was observed as did for other human skeletal muscles. Architectural variables, pennation angle and thickness, were not systematically different between the REF and ECC contractions when FE occurred. Therefore, the results of this study suggest that muscle architecture may have little influence on the production of FE.

• Journal of Korean Physical Therapy Science
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• v.28 no.1
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• pp.11-22
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• 2021

Background: This study was to investigate the effects of active stretching and stability exercise on piriformis muscle thickness and low back pain of male patients with chronic low back pain. Design: Randomized Controlled Trial. Methods: 45 male patients participated in this study. All subjects were randomly assigned. Subjects divided into 15 who underwent contract relaxation (CR) of the proprioceptive neuromuscular facilitation (PNF) to their hip joints, 15 who underwent a combination of isotonic (CI) of the PNF, and the rest 15 who underwent the two techniques (CR+CI). Real-time diagnostic ultrasound was used to measure thickness of the piriformis muscles. The visual analogue scale (VAS) was used to measure degrees of low back pain. A two-way repeated measures ANOVA was used to compare the average values. The SPSS 24.0 was used as the statistical program, and the significance level was set at .05. Results: The CR and the CR+CI groups had more decreased thickness of piriformis muscle when compared to the CI group. The CR+CI group had more decreased pain when compared to the CR and the CI groups. Conclusion: These results suggest that combination of stretching and stability exercise was effective on male patients with chronic low back pain showing limited hip medial rotation.

• Journal of Engineering Education Research
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• v.26 no.4
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• pp.22-35
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• 2023

As information and communication technology has developed remarkably, it has become possible to analyze various types of large-volume data generated at a speed close to real time, and based on this, reliable value creation has become possible. Such big data analysis is becoming an important means of supporting decision-making based on scientific figures. The purpose of this study is to develop a big data analysis tool that can analyze large amounts of data generated through engineering education. The tasks of this study are as follows. First, a database is designed to store the information of entries in the National Creative Capstone Design Contest. Second, the pre-processing process is checked for analysis with big data analysis tools. Finally, analyze the data using the developed big data analysis tool. In this study, 1,784 works submitted to the National Creative Comprehensive Design Contest from 2014 to 2019 were analyzed. As a result of selecting the top 10 words through topic analysis, 'robot' ranked first from 2014 to 2019, and energy, drones, ultrasound, solar energy, and IoT appeared with high frequency. This result seems to reflect the current core topics and technology trends of the 4th Industrial Revolution. In addition, it seems that due to the nature of the Capstone Design Contest, students majoring in electrical/electronic, computer/information and communication engineering, mechanical engineering, and chemical/new materials engineering who can submit complete products for problem solving were selected. The significance of this study is that the results of this study can be used in the field of engineering education as basic data for the development of educational contents and teaching methods that reflect industry and technology trends. Furthermore, it is expected that the results of big data analysis related to engineering education can be used as a means of preparing preemptive countermeasures in establishing education policies that reflect social changes.

• Journal of Veterinary Clinics
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• v.40 no.4
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• pp.308-313
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• 2023

A 1-year-old castrated male Korean Shorthair cat presented with dyspnea, anorexia, lethargy, and seizures. Physical examination revealed salivation, right forelimb hemiparesis, and rapid breathing. No abnormalities were detected on auscultation. Laboratory findings revealed increased levels of bilirubin, aspartate aminotransferase (AST), globulin, glucose, and a decreased albumin-to-globulin (A:G) ratio. Both N-terminal pro-B-type natriuretic peptide (NT-proBNP) and feline serum amyloid A (fSAA) levels were significantly elevated. Thoracic radiography revealed mild cardiomegaly and diffuse increased interstitial infiltration with soft tissue opacity in the periphery of the right caudal pleural space. Echocardiography and lung ultrasonography were performed to investigate the cause of mild cardiomegaly and soft tissue opacity in the pleural space. Echocardiography revealed a mild amount of echogenic pericardial effusion, and lung ultrasonography showed an echogenic soft tissue mass with no blood signal in the right caudal pleural space, suggestive of a granulomatous lesion. After obtaining 5 mL of pericardial fluid through pericardiocentesis, cytology of the pericardial effusion sample revealed marked neutrophils and macrophages with no bacteria. IDEXX feline infectious peritonitis (FIP) virus real-time reverse transcriptase polymerase chain reaction (RT-PCR) confirmed the presence of the FIP virus biotype in the sample. This case presents a rarely reported atypical mixed form of FIP in a cat diagnosed ante-mortem using pericardial effusion analysis. In this case, ultrasound examination played a crucial role in the definitive diagnosis of FIP by PCR biotyping through pericardiocentesis. Ultrasonography can be highly beneficial in guiding the diagnosis and evaluation of cats with suspected FIP.

• Computers and Concrete
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• v.33 no.4
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• pp.399-407
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• 2024

This study nondestructively examined the evolution of crack density in ultra-high performance concrete (UHPC) upon cyclic loading. Uniaxial compression was repeatedly applied to the cylindrical specimens at levels corresponding to 32% and 53% of the maximum load-bearing capacity, each at a steady strain rate. At each stage, both P-wave and S-wave velocities were measured in the absence of the applied load. In particular, the continuous monitoring of P-wave velocity from the first loading prior to the second loading allowed real-time observation of the strengthening effect during loading and the recovery effect afterwards. Increasing the number of cycles resulted in the reduction of both elastic wave velocities and Young's modulus, along with a slight rise in Poisson's ratio in both tested cases. The computed crack density showed a monotonically increasing trend with repeated loading, more significant at 53% than at 32% loading. Furthermore, the spatial distribution of the crack density along the height was achieved, validating the directional dependency of microcracking development. This study demonstrated the capability of the crack density to capture the evolution of microcracks in UHPC under cyclic loading condition, as an early-stage damage indicator.

• Journal of the Korean Society of Radiology
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• v.84 no.1
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• pp.92-109
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• 2023

In patients with thyroid nodules, ultrasonography (US) has been established as a primary diagnostic imaging method and is essential for treatment decision. The Korean Thyroid Imaging Reporting and Data System (K-TIRADS) is a pattern-based, US malignancy risk stratification system that can easily diagnose nodules during real-time ultrasound examinations. The 2021 K-TIRADS clarified the US criteria for nodule classification and revised the size thresholds for nodule biopsy, thereby reducing unnecessary biopsies for benign nodules while maintaining the appropriate sensitivity to detect malignant tumors in patients without feature of high risk thyroid cancer. Thyroid radiology practice has an important clinical role in the diagnosis and non-surgical treatment of patients with thyroid nodules, and should be performed according to standard practice guidelines for proper and effective clinical care.